Christoph Lameter wrote:> True. That is why we want to limit the number of unmovable allocations and > that is why ZONE_MOVABLE exists to limit those. However, unmovable > allocations are already rare today. The overwhelming majority of > allocations are movable and reclaimable. You can see that f.e. by looking > at /proc/meminfo and see how high SUnreclaim: is (does not catch > everything but its a good indicator).

Just to inject another factor into the discussion, please remember that Linux also runs on nommu systems, where things like user space allocations are neither movable nor reclaimable.